The progressive decline of sensory-motor and cognitive performance in the elderly has been well-documented. While many investigators have postulated that deficits in selective attention underlie this decline, definitive evidence has yet to be provided. We propose a series of experiments to assess specific attentional and cognitive capabilities of older persons using electrophysiological measures recorded from the scalp. Extensive studies of normal, young adults in our laboratory and elsewhere have identified four main types of event-related brain potentials (ERPs) that are associated with different aspects of selective attention: (1) the N1 wave (reflecting a focussing of attention on one sensory channel among competing input channels); (2) the P3 wave (associated with sensory recognition and decision-making); (3) the P3a wave (signifying the registration of irrelevant deviations in background stimulation); and (4) the "novelty-P3 wave (elicited when a subject is surprised by a novel visual stimulus). Application of these ERP measures to an elderly subject population will enable us to assess a wide range of attentional capabilities, including the ability to select between different channels of input and to reject irrelevant, intrusive stimuli in the same or different modality. Using these ERP techniques (together with converging behavioral measures of attention) we hope to characterize the attentional capacities of normal, elderly people. These studies will lay the groundwork for future investigations of clinical syndromes associated with aging and senescence where attentional deficits may be a dominant feature.